**6. The perspective of immunological approaches**

Edward Jenner was the first to scientifically prove in studies carried out in 1796, a method to protect against smallpox, thereby laying the foundations of vaccinology, and although the invention is not directly attributed to him, he is often considered the father of vaccines due to his scientific approach that proved that the "vaccination" method worked, and from then until today, more than 200 years after its discovery, new biotechnological tools have substantially improved not only the application of vaccines, but the way to produce them.

A vaccine is a biological preparation that provides an active acquired immunity to a particular pathogen. The vaccine preparation stimulates the immune system to recognize a foreign threat and thus destroys and remembers it, so that the immune system can easily destroy any of these pathogens when they later invade into the body. The vaccine characteristics can be enhanced by Biotechnology.

Vaccines have been the most significant advance in public health, and its preventive prophylactic treatment has been demonstrated as we mentioned, for over 200 years for bacterial and viral diseases preventing morbidity and mortality in millions of people annually [53]. Vaccine development during the pre-genomic era was based on the use of dead, live or attenuated organism or on the use of subunitarian proteins purified from total extracts from organisms of interest [54].

These subunitarian proteins may contain one or more antigens combined. To develop such vaccines is a critical necessary step, identification of proteins of interest and eliminating others that are not useful. In this particular case, in order to be recognized as protector, an antigen must be able to limit the development or reproduction of the organism, parasite or pest in question in subsequent exposure challenges [55].

The empirical approach to the development of subunit vaccines includes several steps: a) culturing the parasite, microorganism or pest to be controlled, b) the analysis, and identification of its components, c) purification of antigens having immunogenic properties required for product development and d) the subsequent challenge with the infectious agent or parasite against which we want to develop the vaccine, in an appropriate animal model to evaluate the immunogenic characteristics of this technology [56, 57].

This methodology has difficulties inherent in the process of identification and purification of the fractions possessing the optimal antigenic characteristics for vaccine development and the availability of macro or microorganism to be controlled by this biotechnological tool because the vaccine production It is severely limited when the target organism cannot easily grow [58]. There are other drawbacks that have to do also with the biology of the target organism, since in some cases the most abundant proteins are not necessarily immunoprotective, or may be the case that the antigens expressed during in vivo or infestation infection as the case are not the same as those expressed during cultivation in vitro latter may not be the case in ticks [59].

Difficult as it may seems, the hard work has already made great progresses, the number of cloned and analyzed genes are already a big list, and experiments have shown that genes as Bm86, subolesin, ferritin, aquaporin and a growing number of orthologous genes can be used to control ticks. The future in the field of vaccine development is becoming shorter, and the scope of modern technology in the field is increasingly longer. Landing knowledge regarding the tick vaccines development for tick control, is very close to pays off as seen by the growing list of new antigens discovered, although the tick control still represents a challenge for the scientific community.
